The objective of this study is to assess the feasibility of a novel approach to phenotyping CYP3A activity using midazolam. The approach proposed will be used to estimate both hepatic and intestinal CYP3A activity in twelve (n-+12) normal healthy volunteers results will be compared to estimates derived from the traditional phenotyping approach. The results of this study will provide important information regarding the feasibility of this phenotyping approach. This approach may then be applied in subsequent investigations exploring factors that modulate CYP3A intestinal and hepatic activity.